Method of forming an electrical connection and electrical connection

Abstract

A method of forming an electrical connection is provided. The method may include: forming a first foldback bond on a first contact element by bonding a first section of a first bonding wire to the first contact element; folding the first bonding wire to arrange a second section of the first bonding wire over the bonded first section; and pressing the second section onto the first section, bonding a third section of the first bonding wire to a second contact element, and bonding a fourth section of the first bonding wire onto the first foldback bond.

What is claimed is: 
     
         1 . A method of forming an electrical connection, the method comprising:
 forming a first foldback bond on a first contact element by bonding a first section of a first bonding wire to the first contact element, folding the first bonding wire to arrange a second section of the first bonding wire over the bonded first section, and pressing the second section onto the first section;   bonding a third section of the first bonding wire to a second contact element; and   bonding a fourth section of the first bonding wire onto the first foldback bond.   
     
     
         2 . The method of  claim 1 , wherein the first foldback bond comprises a flat top surface section for receiving the fourth section. 
     
     
         3 . The method of  claim 1 , wherein bonding the first section of the first bonding wire to the first contact element comprises:
 melting the first section of the first bonding wire to form a free air ball; and   attaching the free air ball to the first contact element.   
     
     
         4 . The method of  claim 1 , wherein bringing the first bonding wire back to the first foldback bond comprises forming a loop with the first bonding wire. 
     
     
         5 . The method of  claim 1 , wherein bringing the first bonding wire back to the first foldback bond comprises decreasing an angle α between the first bonding wire and the second contact element to arrange a fifth section of the first bonding wire vertically adjacent to or in contact with the third section. 
     
     
         6 . The method of  claim 5 , wherein decreasing the angle α between the first bonding wire and the second contact element comprises pulling the first bonding wire towards the first contact element and/or pressing the first bonding wire towards the second contact element. 
     
     
         7 . The method of  claim 5 , further comprising:
 bonding a sixth section of a second bonding wire onto the fifth section and bonding a seventh section of the second bonding wire onto the fourth section; or   bonding a sixth section of a second bonding wire onto the fourth section and bonding a seventh section of the second bonding wire onto the sixth section.   
     
     
         8 . The method of  claim 7 , wherein bonding the sixth section onto the fourth section or the fifth section comprises:
 melting the sixth section of the second bonding wire to form a third free air ball; and   attaching the third free air ball to the fourth section or the fifth section, respectively.   
     
     
         9 . The method of  claim 8 , further comprising:
 bonding an eighth section of the second bonding wire to the sixth section.   
     
     
         10 . The method of  claim 8 , further comprising:
 forming a second foldback bond on the fourth section or on the fifth section by bonding the sixth section of the second bonding wire to the fourth section or on the fifth section, respectively;   folding the second bonding wire to arrange the eighth section of the second bonding wire over the bonded sixth section; and   pressing the eighth section onto the sixth section.   
     
     
         11 . The method of  claim 10 , further comprising:
 bonding a ninth section of the second bonding wire onto the eighth section.   
     
     
         12 . The method of  claim 5 , further comprising:
 alternating between the first contact element and the second contact element for bonding consecutive portions of the first bonding wire alternatingly on top of the fourth section of the first bonding wire and the fifth section of the first bonding wire, respectively.   
     
     
         13 . The method of  claim 1 , wherein the free end of the first bonding wire is still attached to the third section of the first bonding wire while the free end is being brought back to the first foldback bond. 
     
     
         14 . The method of  claim 1 , wherein the second contact element comprises a padding element formed on a second contact pad or lead, and wherein the third section of the first bonding wire is bonded to the padding element. 
     
     
         15 . The method of  claim 14 , wherein the padding element is a bump formed by melting a portion of a third bonding wire to form a second free air ball and bonding the second free air ball to the second contact pad or lead. 
     
     
         16 . An electrical connection, comprising:
 a first contact element;   a second contact element;   a first foldback bond on the first contact element comprising a first section of a first bonding wire bonded to the first contact element, and a second section of the first bonding wire that is folded back over and bonded onto the bonded first section;   a third section of the first bonding wire bonded to the second contact element; and   a fourth section of the first bonding wire bonded onto the first foldback bond.   
     
     
         17 . The electrical connection of  claim 16 , wherein the first foldback bond comprises a flat top surface to which the fourth section is bonded. 
     
     
         18 . The electrical connection of  claim 16 , wherein the first contact element and/or the second contact element is selected from the group of contact elements consisting of: a chip contact pad; a leadframe; a lead; a clip; and a contact area of a printed circuit board. 
     
     
         19 . The electrical connection of  claim 16 , wherein the first bonding wire forms a loop between the third section and the fourth section. 
     
     
         20 . The electrical connection of  claim 16 , wherein the first bonding wire further comprises a fifth section that is arranged vertically adjacent to or in contact with the third section. 
     
     
         21 . The electrical connection of  claim 20 , wherein an angle α between the fifth section of the first bonding wire and the second contact element is an acute angle. 
     
     
         22 . The electrical connection of  claim 20 , further comprising:
 a sixth section of a second bonding wire bonded onto the fifth section and a seventh section of the second bonding wire bonded onto the fourth section; or   a sixth section of a second bonding bonded onto the fourth section and a seventh section of the second bonding wire bonded onto the fifth section.   
     
     
         23 . The electrical connection of  claim 22 , wherein a material of the second bonding wire is identical to a material of the first bonding wire. 
     
     
         24 . The electrical connection of  claim 23 , further comprising:
 an eighth section of the second bonding wire bonded onto the sixth section.   
     
     
         25 . The electrical connection of  claim 20 , further comprising:
 a second foldback bond comprising a sixth section of the second bonding wire bonded to the fifth section or to the fourth section; and   an eighth section of the second bonding wire that is folded back over and bonded onto the bonded sixth section.   
     
     
         26 . The electrical connection of  claim 25 , further comprising:
 a ninth section of the second bonding wire bonded onto the eighth section.   
     
     
         27 . The electrical connection of  claim 21 , wherein consecutive portions of the first bonding wire are bonded alternatingly between the first contact element on top of the fourth section of the first bonding wire and the second contact element on top of the fifth section of the first bonding wire, respectively. 
     
     
         28 . The electrical connection of  claim 16 , wherein the first bonding wire comprises or consists of at least one of a group of metals selected from the group consisting of:
 copper; gold; and silver.   
     
     
         29 . The electrical connection of  claim 16 , wherein the second contact element comprises a padding element, and wherein the third section of the first bonding wire is bonded to the padding element. 
     
     
         30 . The electrical connection of  claim 29 , wherein the padding element is formed from bonding wire, optionally from the first bonding wire. 
     
     
         31 . The electrical connection of  claim 29 , wherein a material of the padding element is identical to a material of the first bonding wire.